I grow in the greenhouse year round, and for quite a few of my plants I use 3 gallon pots as the final pot for the plant. These plants get watered automatically twice a day in the summer, and once a day in the winter. These pots are larger, or comparable to what commercial growers use to grow greenhouse crops of bell peppers. I have in the past made comparisons with larger pots, and have not seen a significant increase in size with the larger pots. The larger pots do give me a bit more wiggle room if the drip system fails. With the small pots, a missed irrigation will cause the plants to start to wilt on a hot day. I use a peat-based potting mixture similar to some used commercially, and find that my best performance comes with almost constant low-level fertilization through the irrigation water. I've in the past started quite a few plants early as discussed here. Even if I keep the plants in 1 gallon containers, I get good growth. The smaller containers allow me to grow more varieties.
Renais